Cross roller earth boring drill



' Oct. 24, 1939.

c. E. REED 2,177,334

CROSS ROLLER EARTH BORING DRILL Filed May 23, 1938 2 Sheets-Sheet l 31wWM:

Clazence EReed,

Gianna/1344 Oct. 24, 1939. c. E. REED 2,177,334

CROSS ROLLER EARTH BORING DRILL Filed May 23, 1938 2 Sheets-Sheet 2Patented Oct. 24, 1939 R I MAY 16 1940 UNITED STATES CROSS ROLLER EARTHBORING DRILL Clarence E. Reed, Wichita, Kana, assignor to ChicagoPneumatic T N. Y., a corporation 00] Company, New York, of New JerseyApplication May 23, 1938, Serial No. 209,563

Claims.

The invention concerns an earth boring drill and is disclosed inconnection with the general type known as a cross roller bit in which aplur'ality of roller cutters are arranged in the same diametrical planeand cut the major portion of the formation, and inclined side cuttersarranged in a diametrical plane substantially at right angles to theplane in which the first mentioned cutters are located, cut the area atthe margin of the bottom of the hole being bored.

One object of the invention is to provide a cutter assembly which willstand up to its work by taking care of end thrust of the cutters,thereby eliminating or reducing to a minimum the wear due ordinarily tosaid end thrust, and preventing the formation of tapered holes whichrequire reboring at great expense.

Otherobjects will be clear from the following disclosure.

It will be, understood that while the invention is illustrated inconnection with an earth boring drill of the cross roller type, it isnot limited as to all of its aspects thereto.

In the drawings Figure 1 .is a central vertical sectional view of onehalf of a drill bit head, showing one of the side roller cutters and itsspindle and roller bearing assembly.

Fig. 2 is a central vertical sectional view of a bit head in a plane aquarter turn from the plane of section of Figure l, and showing a pairof roller. cutters arranged substantially end to end in axial alignment,and constituting the cross roller assembly per se.

Fig. 3 is a side view of one of the spindle members of the assemblyshown in Figure 1.

Fig. 4 is a side view of the other spindle mem ber belonging to the sideroller cutter organization of Figure 1.

In these drawings, l indicates the main body of a bit head ofsubstantially ordinary form having a threaded shank 2 for attachment toa drill stem. As in usual practice, the bit head is hollow to receiveflushing fluid which is directed through openings 3 and 4 to the toothedroller cutters to keep them free from accumulations of the cutformations, and to cause the discharge of said material from the borehole. r I

A strut 5 depends from the lower face of the bit head being formeddesirably integral therewith. Main spindle units as shown in Fig. 2marked 6, 1 are arranged below the lower face of the bit head, eachhaving a shank or hanger portion 8. seated in a recess in the side ofthe bit head wherein it is weldedyas shown at 9, said spindle member andshank preferably being formed in one piece. The spindle members 6 and lhave each a reduced diameter part 6a, Ia substantially meeting ,at theirend faces, the separation between them being slight but adapted toreceive welding mate- 5 rial by which the two spindle units may be connected. The two cutter units of Fig. 2 provide what are usually calledthe cross roller cutter, made up of substantially cylindrically shapedcutters 9 and I0 toothed on their exterior to per- 10 form cuttingactions on the formation. This toothed formation may assume variousforms, but

in the particular assembly illustrated, each may consist of two circularrows of teeth a at the outer end portion of the cutter, a single row ofteeth I) at the inner end of the cutter, and a spiral rib 0 having anumber of turns about the cutter and occupying the space between thecircular rows of teeth a, b, the' purpose of this toothed arrangementbeing to provide efiicient means for breaking up or disintegrating theformation as rapidly as possible.

The spindle assembly for the cross roller cutters 9 and I0 includesimilar features, and it will be sufficient to describe one of saidassemblies. Re- 5 ferring, therefore, to the righthand assembly in Fig.2, it comprises the main spindle portion 1 of' comparatively largediameter and its extension la of reduced diameter, and annular flangesll, l2, and I3. The flanges II and I3 present on one side, surfaceslying in planes at right angles to the axis of the spindle, and thusfurnish the end walls of raceways for cylindrical roller bearings M,which find complementary surfaces upon which to roll on the bore wall ofthe roller cutter l0 and on the cylindrical periphery of the spindle I.The flanges II also present frusto-conical surfaces l5 which form wallsof frusto-conical raceways, the complementary frustoeconical racewaysurfaces of which are on the bore wall of the cutter and on spindleportions adjacent the ends of the roller cutter.

These frusto-conical raceways receive frustoconical roller bearings l6and H. The larger diameter ends of those marked I! are directedoutwardly from .the vertical axis of the drill, and hence take endthrust of the roller cutter in a direction radially outward from thecenter of rotation of the drilL Those frusto-conical roller bearingsmarked I6 take end thrust of the roller cutter ID in a directioninwardly towards the vertical axis of the drill.

Both sets of frusto-conicalroller bearings take thrustsof the rollercutter radial to the axis individual to said -cutter,,and also some ofthe upthrust from the bottom of the hole. The major portion of thisupthrust or radial thrust of the cutter is borne, however, by the twosets of cylinder roller bearings ,Il in the cylindrical raceway dividedby the annular flange l2.

The frusto-conical raceway for the frus'to-conical bearing rollers I1 isformed in the base or enlargement l8 integrally connecting the sidehanger or bracket 8 and the spindle portion 1, said enlargement or basemember being undercut at [5a to furnish the outer wall of the raceway ofwhich the surface IIa furnishes the frusto-conical bearing surface.

The frusto-conical raceway for the frusto-conical roller bearings I6 isprovided by the separate spindle member or collar 16a having a centralopening to fit the reduced diameter portion Ia of the spindle member I,an undercut surface lBb serving as the defining wall of thefrusto-conical raceway at the large diameter end of the frustoconicalroller bearing.

The spindle section Ilia has a cylindrical exterior which fits in partinto the cylindrical counterbore Illa at the inner end of the rollercutter. This collar or spindle section also fits in part in a recess inthe strut or bridge piece 5. This recess may be in the form of adownwardly open notch 5a in the lower edge portion of said bridge.

The spindle section or collar lib fits against a similar spindle sectionor collar belonging to the spindle assembly of the lefthand cross rollercutter! of Fig. 2. These collars may be welded together. I

The spindle and roller bearing assembly for the, cross roller cutter 9,Fig. 2, is substantially the same as above described, the maindifference being that the cutter 9 is shorter than the roller cutter l0,and hence one set of cylindrical roller bearings Ila are used instead oftwo spaced apart rows, as in the case of roller cutter Ill.

Referring to. Figure 1, which shows one of the side roller cutterassemblies of which, as in ordinary practice, there are two located in avertical plane 90 from the plane of Fig. 2, it will be noted that theside roller cutter I9 is mounted to rotate in a plane incliningdownwardly and outwardly in relation to the vertical axis of the drillindicated at a:-:r. This roller cutter is generally of cylindrical formhaving peripheral teeth for disintegrating the formation.

' These side roller cutters determine the diameter of the bore hole, itbeing noted that they cut clearance beyond the outermost surface of thebit head, or the brackets 8 or 8a thereof. It is important' that endthrust of these cutters be taken care of to the fullest extent. In.carrying out this object, as well as to secure long service of theseside cutters, the body of the cutter is made wider than the toothedsurface, for which purp se an extension or hub portion is provided at20. By this addition, a longer bore is provided within the cutter thanin ordinary practice, and I am thereby enabled to employ afrusto-conical raceway surface ateach end of the bore of the cutter, inaddition to a cylindrical raceway surface, said surfacesbeing marked 2|,

22, and 23, Fig. 1. Roller bearings are provided.

at 2la, 22d, and 23a conforming to these raceway surfaces, those marked2la and 2211 being' frusto-conical with their larger diameter endsdirected in opposite directions, so that end thrust of the cutter ineither inward or outward direction relative to the vertical axis of thedrill will be taken by either one or the other of said frusto-conicalroller bearings. Radial thrusts of the roller cutter and upthrusts fromthe bottom of the bore hole will be taken mainly by the cylindricalroller bearings 23a, and as the frusto-conical roller bearings therebywill be relieved of the major portion of these upthrusts and radialthrusts of the cutter, the said frustoconical roller bearings will havea longer life than if they took all thrusts imposed upon the cutter,including the end thrusts. With my present improvement, the side rollercutters will maintain their position relative to-the prescribed diameterof the bore hole by reason ofthe frusto-conical roller bearingsstandingup to their work for a larger period of time owing to beingrelieved in large measure by the cylindrical roller bearings from radialand upthrusts. 'By

maintaining their prescribed positions, said side roller cutters willprevent the formation of a tapered bore hole, and the great expense ofreboring to eliminate the taper.

The roller bearings of these-side cutters run in raceways of a spindleassembly consisting of a main cylindrical spindle section 24, a flange25 defining on one side the wall of a cylindrical raceway for thecylindrical roller bearings 23a, and presenting on its other side theinclined shoulder 26, defining the inner limit of the; frusto-conicalraceway 21, the other side of! which is furnished by undercutting theshoulder or base 29, as at 28, of the hanger or bracket 8a, which, as inordinary'practice, is welded or secured to the outer side of the bithead'l.

Thespindle assembly is completed by a spindle member adapted to beslipped onto the main cylindrical part 24 of said spindle assembly. Thiscollar member or removable spindle section is shown in side view in Fig.4, and in section in Fig. l, the latter figure showing it in itsassembled relation to the main spindle portion. It has a cylindricalbody part 24a, a flange 250. with an inclined side 26a, defining theinner limit of a frusto-conical. raceway surface 21a, also a flange 29aundercut to provide an inclined shoulder or bearing wall 28a. Thisformation provides the cylindrical raceway for the roller bearings 23aand the frusto-conical roller bearings 22a.

It will be noted that in devising the roller bearing assembly associatedwith the side roller cutter, I not only form the body of said rollercutter with a hub extension 20 on one side, but I take advantage of thefull length of the bore wall of the cutter. In other words, the outeredge of the frusto-conical raceway surface of the bore wall coincideswith the edge of the bore. This enables me to space the sets offrusto-c'onical cutters apart a suflicient distance to accommodate thecylindrical roller bearings and the raceway structure of the spindle forall of the sets of roller bearings.

In both assemblies of roller bearings, i. e.,- of Fig. 2 as well as inFig. 1, the employment of the cylindrical roller bearings in associationwith the two sets of frusto-conical roller bearings which take the endthrusts, largely relieves these sets of frusto-conical rollers of wear,thereby enabling the latter to maintain the roller cutters in theirprescribed relation to" the center of the bore hole, with the result, inrespect to the side roller cutters, that the prescribedsdiameter of holewill be maintained instead of producing a tapered'hole, and in respectto the cross 'roller cutters, the result will be that said cutters willtraverse their prescribed paths during 36 mately horizontal axis, atoothed roller cutter the eifectlve life or the cutter teeth, andwobbling of .thedrill bit as a whol will be prevented.

I'claim: a 1. A roller cutter'for an earth boring drill having a toothedexterior and a bore substantially longer than the width of the cuttingsurface,

said bore having roller bearing raceway surfaces, one at each endportion of said bore tapered inwardiyoi the cutter and providing bearingsurfaces for frusto-conical roller end thrust bearings, said tapered endportions terminating substantially in the planes bounding the ends orsaid cutter bore.

2. A cross roller cutter assembly comprising a bit head having acentrally disposed depending strut provided with an opening, a mainspindle member on each side of the strut, removable spindle memberssubstantially abutting each other in the opening of the strut, each ofsaid removable members having a portion, contacting the strut, and atapered raceway racing outwardly, and each having a recess disposedsub-- stantially centrally thereof, said main spindle portions havingprojections-on which the removable spindle portions are mounted by saidrecesses, said main spindle portion having a flange adjacent thetaperedraceway to provide a wall therefor, tapered end thrust roller bearingsin said raceway, a cutter on the spindle mounted on said rollerbearings, and a support at the outer end of each main spindle member,substantially as described.

3. An earth boring drill oi! the cross-roller type comprising a spindle,means engaging the ends of the spindle for supporting it on anapproxisurrounding and rotatably mounted on the spindle, two spaced setsof rrusto-conical roller bearings, one set adjacent each end of thespindle and between the cutter and spindle, said sets' of roller,bearings tapering in opposite directions whereby to sustain horizontalthrusts on the cutter in opposite directions and a part oi. the verticalthrusts, a set of cylindrical roller-bearings positioned between saidi'rusto-conical bearings,

whereby to sustain vertical thrusts on the cutter in a directionperpendicular to the axes of the cylindrical roller bearings, andcomplementary raceways in the cutter and spindle respectively for saidroller bearings.

4. A roller cutter and spindle assembly for an earth boring drill, saidcutter having a toothed exterior and a bore longer than the width ofsaid toothed exterior, a set of frusto-conical and thrust rollerbearings at each end of the bore, a frusto-conical raceway surface ateach end of said bore, for said end thrust bearings, a

spindle support and a spindle having raceway 1 surfaces, one for each ofsaid sets of frusto-conical roller bearings, said spindle racewaysurfaces lying partly outside the planes bounding the ends of saidcutter bore, said bore and said spindle having each a bearing surface ofsubstantial width intermediate the said frusto-conical raceway surfaces.

5. A roller cutter and spindle assembly for an earth boring drill.according to claim 4 in which the spindle comprises a main section and aremovable section connected therewith, the said main section having ashoulder undercut beyond raceway and the said intermediate bearingsurfaceof the wall of the cutter bore, the flanges of said spindlesection providing walls defining the limits of the cylindrical racewayand between which walls the cylindrical anti-friction roller bearingsare guided, substantially-as described.

CLARENCE E. REED.

